I ALIGNMENT PROCEDURE
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89 OA
Step 1. High-Voltage Test
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See Preliminary of Service Section and Figure 6A.
Step 2 Preturn-on Adjustments
A. Set voltmeter and ammeter to zero.
B. Set programming control full clockwise.
I C, Set line switch to off .
D. Check for proper fuses (DC 1 amp, AC 5 amp).
E. Wire for normal operation, see Figure 1.
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1 F. Disconnect main power rectifier from T3 (lugs 11 & 12) .
Step 3. Turn on Unit
I ~ Output voltage should rise to about 20 volts.
Step 4. Connect A1 to +Output
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Output voltage should fall to zero. If 3 or 4.are not correct, check voltages
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1 through 7 in Table I and check Q1, 2, 5, 7, 8, 9.
1 Step 5. Connect a 0-1 .O amp ammeter directly across the output terminals. Adjust
P4 for .8 ampere on external meter. Adjust P7 for 08 ampere on internal
meter. Remove meter.
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Step 6. Turn programming control down until supply goes into regulation-about 3/4
I turn from full counterclockwise. Rock control up and down. Connect an
I oscilloscope between minus bus and test point 30. Waveform should shift
left and right. See Figure 6B. Improper waveform indicates trouble in SCR
, control circuit .
Step 7. Turn control about one turn up from full counterclockwise . Connect scope
I between the cathode and gate of each SCR and observe waveforms as in
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Figure 6C. A very low on high pulse voltage usually indicates a defective
SCR.
1 Step 80 Adjust output voltage to about 5 volts. Load supply to .65 amperes ard
observe output voltage with scope. The peak-to-peak ripple should be less
I than 300yv.
Step 9. Turn off unit and reconnect the main rectifier bridge to lugs 11 and 12 on
T3 . Set programming control to one turn from full clockwise. Turn on unit.
I Output voltage should rise to about 300 volts. Observe output voltage on
scope, Ripple should not exceed 300yv peak-to-peak. |
ACEC
HEWLETT-PACKARD
